Dunbar's Number is a postulate claiming that due to how human brains are structured, there is an upper limit to number of personal relationships we can keep track of. Commonly, that number is presumed to be about 150; though the science is not nearly as sure of that number. This 150 includes all of your personal relationships:
- Family
- Coworkers
- Friends
- People you run into every day and have learned their names
And so on.
This postulate has an intersection with growing a company, and how the office culture evolves. When a company is 4 people in a shared open-plan office, it's quite easy for everyone to know everything about everyone else. You can still kind of do that at 20 people. Getting to 50 starts pushing things, since 'coworkers' begins to take up a large piece of a person's personal-relationship social graph. At 100, there are going to be people you don't know in your company. As it evolves, office-culture needs to deal with all of these stages.
One of the critiques to Dunbar's Number, more of a refinement, is a report by Matthew Brashears (doi 10.1038/srep01513) that claims humans use compression techniques to expand the number of storable relationships. The idea is, in essence:
If the structure of relationships has an external framework, it is possible to infer relationships. Therefore, humans do not have to memorize every leg of the social-graph, which allows them to have more connections than otherwise are possible.
One such external structure has direct relevancy to how offices work: kin-lables.
The example used in the report are things like son, daughter, uncle, father. English is not a concise language for describing complex family structures, so I'll use something it is good at: company org-charts.
If you are a Senior Software Engineer in the Dev Team, you probably have a good idea what your relationship is with a generic QA Engineer in the QA Team. This relationship is implied in the org-chart, so you don't have to keep track of it. The QA team and engineering work together a lot, so it's pretty likely that a true personal relationship may be formed. That's cool.
Scaling a company culture begins to hit problems when you get big enough that disparate functional groups don't know each other except through Company Events. Take a structure like this one:
When the company is 20 people, it is entirely reasonable for one of the software engineers to personally know all of the marketing and sales team (all three of them). At 75 people, when each of these directorates have been fleshed out with full teams, and both Marketing and Engineering have split sub-teams for sales, marketing, front-end, and back-end, it is far less reasonable for everyone to know everyone else; there is little business-need for the back-end engineers to have any reason to talk to the sales team for any reason other than at Company Events.
This is where the cunning Director of Culture can start building in structure to stand in for the personal relationships it is increasingly impossible to maintain. All-hands Company Events help maintain the illusion of knowing everyone else, at least on a nodding basis. Another way is to start fostering team-relationships across org-chart boundaries using non-business goals, such as shared charity events. This would allow members of the Back-End Team to have a relationship with the Sales Team, which would further allow the individual members of the teams to infer personal relationships with the other team.
This only kicks the can down the road, though.
There will come a time when it will be simply impossible for everyone to know everyone else, even with fully implicit relationships. There will be parts of the company that are black boxes, shrouded in mystery, filled with people you didn't even know existed. A 500 person company is a very different thing than a 100 person company.
As a company grows, they will encounter these inflection points:
- Personal relationships can't be held with everyone in the company.
- Implicit relationships can't be held with everyone in the company.
- Parts of the company are largely unknowable.
As the company gets ever larger, the same progression holds within divisions, departments, and even teams. The wise manager of culture plans for each of these inflection points.